Immigrant children living in poverty are disproportionately exposed to family/social, economic, cultural, and community level adversities. The autonomic nervous system (ANS) responds to adversities or stressors by the activation of the sympathetic nervous system (the flight or fight response) and withdrawal of the parasympathetic nervous system (the resting response). Autonomic reactivity, a measure of this physiologic response, may be influenced by early adversities and may function as a moderator of vulnerabilities (e.g., mental health problems) later in life. Because there are no prior longitudinal studies, it is not known if young children's exposure to cumulative adversities, from infancy to five years of age, affects their biologic patterns of resting and response to challenge by five years of age and if these biologic responses affect children's later mental health. The Center for the Health Assessment of Mothers and Children of Salinas (CHAMACOS) is a longitudinal birth cohort study (born in 2000) of approximately 500 economically impoverished immigrant Latino mothers and children living in the agricultural community of the Salinas Valley, CA. This population is at high risk for mental health problems. At multiple points (6 months, 1, 2, 31/2, 5, 7 years), we collected information from the mothers and from home visits on many environmental stressors. On 389 of these children, we also conducted assessments of resting and reactivity measures of ANS. When the children were seven years of age, we collected information on their symptoms of aggression and depression, as rated by their mothers, teachers and themselves. This application aims to conduct secondary data analyses to examine the relationship between changes in exposure to adversities and changes in autonomic resting and reactivity measures from six months to five years of age and to determine whether their autonomic trajectory predicts symptoms of aggression and depression at seven years of age. The proposed study will directly address the call of the recent IOM, From Neurons to Neighborhoods, for additional research to examine the interaction between biology and experience in understanding child development. Our research findings may provide key information about children's resiliency/vulnerability and prevention of mental health problems in this growing at-risk population. PUBLIC HEALTH RELEVANCE: Poor, immigrant children exposed to many family/social, economic, cultural, and community adversities during the first five years of life may develop a dampened or heightened physiologic response to their environment. Also, children with slow heart rates at five years of age may develop symptoms of aggression, while children with fast heart rates may develop symptoms of depression by school-age.